three missionaries and three cannibals must cross a river using a boat which can carry at most two people, under the constraint that, for both banks, if there are missionaries present on the bank, they cannot be outnumbered by cannibals (if they were, the cannibals would eat the missionaries.) The boat cannot cross the river by itself with no people on board. Move all missionaries and cannibals from one river bank to the other.

All 3 missionaries should go across, leaving two on the opposite bank. One missionary returns to retrieve 2 cannibals, leaving then with the two missionaries already on the opposite bank, then returns for the last cannibal.

That is an incorrect answer. The boat can not hold more than 2. 1M + 1C take the boat and leave 1C on the other side. 1M (left in the boat) goes back and takes 1C. They cross and 1M stays on the other side. 1C (left in the boat) goes back and takes 1M and drops him off on the other side. 1C (left in the boat) goes back and takes the last 1M and drops him off on the other side. 1C (left in the boat) goes back and takes the last 1C and cross the river.

This took me off guard. The information required can be found anywhere on the web.. throughout my answer I was prodded for more information... question was oriented towards have you implemented said architecture. If you don't know it, don't B.S. Answer with what you know.

I felt badly using the same story over and over, but I recounted a time where my team challenged me as CTO, which was quite remarkable since culturally they were reticent to do so, and there was a tremendous gap in experience. But, they did, it was right, and their solution was the best answer to the problem.